Sidonius (Speaking Of King Theodoric Of The Goths, A.D. 454-526)
"It is a fact that it was formerly the custom in the East to keep the Sabbath in the same manner as the Lord's day and to hold sacred assemblies: while on the other hand, the people of the West, contending for the Lord's day have neglected the celebration of the Sabbath." "Apollinaries Sidonli Epistolae," lib.1, 2; Migne, 57.But the seventh day is the sabbath of the LORD thy God:
Exodus 20:10